Strongly enhanced pinning force density in YBCO–BaTiO 3 nanocomposite superconductor

Abstract

YBa 2Cu 3O 7−δ–BaTiO 3 (4 wt.%) (YBCO–BTO (4%)) composite bulk polycrystalline sample has been synthesized by solid state reaction method. The structure of composite sample has been investigated by X-ray diffraction and magnetization measurements were carried out using MPMS SQUID VSM. The superconducting transition temperature of the YBCO–BTO (4%) sample was similar to that of pure YBCO. The critical current density ( J c ) for YBCO–BTO (4%) sample increases significantly as compared to pure YBCO sample. The enhancement of the critical current density in the YBCO–BTO (4%) sample has been attributed to the presence of BaTiO 3 nanoparticles acting as artificial pinning centres. The introduction of BaTiO 3 particles in YBCO increases pinning force density from 0.71 GN/m 2 to 1.41 GN/m 2 at 4 K and 0.33 MN/m 2 to 0.97 MN/m 2 at 77 K.